Vlad Sorry you keep asking for steps to reproduce. The people here are describing the exact steps. It happened to me twice today since the latest update. I clicked on a folder full of my most important bookmarks, in the bookmarks bar, and it deleted the whole folder. When I hit undo it brought the folder back but it is totally empty. Those are the steps. It happens randomly so there is no actual pattern to it, or any specific path. It just happens. It looks very much like a bug in the browser.